Method for making plywood

ABSTRACT

Method for producing plywood comprises steps of delivering first veneer with adhesive on upper surface thereof from first station to main conveyor running transverse to direction of delivery of first station to main conveyor running transverse to direction of delivery of first veneer. Method also includes step of delivery second veneer with adhesive on upper surface thereof and grain thereof transverse to grain of first veneer from second station independent of first station to main conveyor. Second veneer is compiled on top of first veneer, and thereafter several additional veneers with adhesive on upper surfaces thereof are independently delivered from additional stations to main conveyor. Additional veneers have alternating grain directions and are compiled on top of one another and first and second veneers. Finally, uppermost veneer without adhesive thereon is delivered from final station to main conveyor, and thereafter uppermost veneer is compiled on top of other veneers so that grain thereof is transverse to grain of adjacent veneer.

March 1974 MASAICHIRO MATSUMOTO ETAL 3,795,560

METHOD FOR MAKING PLYWOQD 4 Sheets-Sheet 1 Filed July 22, 1971MASAICHIRO MATSUMOTO ETAL 3,795,560

March 5, 1974 METHOD FOR MAKING PLYWOOD 4 Sheets-Sheet 2 Filed July 22,1971 March 1974 MASAICHIRO MATSUMOTO EI'AL 3,795,560

METHOD FOR MAKING PLYWOOD Filed July 22, 1971 4 Sheets-Sheet 5 March1974 MASAICHIRO MATSUMOTO ETAL 3,7

METHOD FOR MAKING PLYWOOD 4 Sheets-Sheet 4 Filed July 22, 1971 US. Cl.156300 2 Claims ABSTRACT OF THE DISCLOSURE Method for producing plywoodcomprises steps of delivering first veneer with adhesive on uppersurface thereof from first station to main conveyor running transverseto direction of delivery of first veneer. Method also includes step ofdelivering second veneer with adhesive on upper surface thereof andgrain thereof transverse to grain of first veneer from second stationindependent of first station to main conveyor. Second veneer is compiledon top of first veneer, and thereafter several additional veneers withadhesive on upper surfaces thereof are independently delivered fromadditional stations to main conveyor. Additional veneers havealternating grain directions and are compiled on top of one another andfirst and second veneers. Finally, uppermost veneer without adhesivethereon is delivered from final station to main conveyor, and thereafteruppermost veneer is compiled on top of other veneers so that grainthereof is transverse to grain of adjacent veneer.

BACKGROUND OF THE INVENTION The present invention relates to a methodfor producing plywood comprising a plurality of individual wood veneers.

Prior to the present invention numerous procedures have been proposedfor producing plywood sheets. One of the prior art plywood producingprocedures involves coating individual wood veneers and compilingplywood sheets by delivering and stacking one veneer after the other ata single processing station. The efficiency of such an operation isquite low.

SUMMARY OF THE INVENTION Accordingly, it is an object of the presentinvention to avoid the shortcomings of the prior art by providing aunique method for producing plywood in a beneficial and highlyeconomical manner.

Another object of the present invention is to provide a method ofproducing plywood wherein adhesive material is applied to the woodveneers in a manner that avoids irregularities of the coating on theveneer.

In accordance with the present invention, a method for producing plywoodcomprising a plurality of veneers includes the step of delivering afirst veneer with adhesive on the upper surface thereof from a firststation to a main conveyor line that runs transverse to the direction ofdelivery Of the first veneer. Next, a second veneer with adhesivethereon and the grain direction thereof transverse to the grain of thefirst veneer is delivered from a second station independent of the firststation to the main conveyor line. The second veneer is compiled on topof the first veneer. Several additional veneers with adhesive thereonand alternating grain directions are independently delivered fromadditional stations to the main conveyor line, and these additionalveneers are compiled on top of one another and the first and secondveneers. Finally, an

United States Patent ice uppermost veneer without adhesive thereon isdelivered from a final station to the main conveyor line, and thereafterthe uppermost veneer is compiled on top of the other veneers so that thegrain thereof is transverse to the grain of its adjacent veneer.

The plywood producing method of the present invention may also includethe steps of applying adhesive to the upper surface of each veneerexcept the uppermost one by applying the adhesive along the veneers inthe same direction as the grain thereof.

BRIEF DESCRIPTION OF THE DRAWING Novel features and advantages of thepresent invention in addition to those mentioned above will becomeapparent to those skilled in the art from a reading of the followingdetailed description in conjunction with the accompanying drawingwherein:

FIG. 1 is a top plan view of an apparatus utilizing the method of thepresent invention;

FIGURE 2 is a simplified side elevational view part of which is in crosssection of the apparatus shown in FIG. 1;

FIG. 3 is a perspective rear view of the veneer carrier of the apparatusshown in FIG. 1;

FIG. 4 is an enlarged cross sectional view taken along line 44 of FIG.1;

FIG. 5 is an enlarged cross sectional view taken along line 55 of FIG.1;

FIG. 6 is an enlarged cross sectional view taken along line 66 of FIG.1;

FIG. 7A is a fragmental top plan view of the vacuum conveyor as used inthe apparatus of FIG. 1;

FIG. 7B is a fragmental cross sectional view in elevation of the vacuumconveyor as used in the apparatus of FIG. 1;

FIG. 8 is a side elevational view illustrating the downstream end of themain conveyor of the apparatus of FIG. 1; and

FIG. 9 is a simplified perspective view illustrating the structure forstacking plywood.

DETAILED DESCRIPTION OF THE INVENTION Referring in more particularity tothe drawing, FIGS. 1 and 2 illustrate a plywood producing machine thatutilizes the method of the present invention. The machine has aplurality of conveyors 1 that form a main conveyor line. The primarypurpose of the main conveyor line is to carry and transport individualwood veneers from left to right, as viewed in FIGS. 1 and 2. The path ofmotion of the main conveyor line is next to a series of individualapparatus stations 2-1, 2-2, 2-3, 2-4 and 2-5. Each of these apparatusstations functions to deliver plywood veneer to the main conveyor line.

As viewed in FIG. 1, the apparatus stations 2-1, 2-3 and 2-5 are locatedat the left end, center and right end of the main conveyor line. Theseapparatus stations provide veneers which have grain directions parallelto the direction in which the veneers are delivered to the mainconveyor. As shown in FIG. 1, the direction of delivery of the veneersto the main conveyor is transverse to the direction of travel of themain conveyor.

The apparatus stations 2-2 and 2-4 are located directly to the left andright of the center apparatus station 2-3. These stations provideveneers having grain directions transverse to the direction of deliveryof the veneers to the main conveyor line. In other words, in theapparatus stations 2-2 and 2-4 the grain of the veneers is transverse tothe direction the veneers are delivered to the main conveyor.

Primarily, the individual apparatus stations along the path of travel ofthe main conveyor 1 function to deliver plywood veneers to the mainconveyor. The individual veneers are compiled one above the other asthey travel along the path of the main conveyor. Since every otherapparatus station delivers veneers having similar grain orientations butdifferent from the balance of the vaneers, the plywood produced hasadjacent veneers of different grain orientation.

As shown best in FIG. 3 a carrier 3 is associated with each of theapparatus stations at a location on the main conveyor. Each carrier haselongated slots 3 which allow pushers 4' to pass therethrough. When aveneer is placed on a carrier 3, the pushers 4 force the veneer off thecarrier onto the conveyor 1 where it is conveyed to the next station ata location below the carrier associated with the next station.

The apparatus for feeding a veneer to the main conveyor is constructedas follows. As shown best in FIG. 4, a lifter 5 in each of the apparatusstations 2-1, 2-3 and 2-5 provides a veneer A-1 having a grain directiontransverse to the movement of the main conveyor 1. The uppermost surfaceof the individual veneers A-l located on the lifter 5 partly faces theleading end of a suction device 6' associated with a vacuum feeder 6.The suction mouth 6' also faces part of the leading end of a conveyor 7.When an air cylinder 8 is operating the vacuum feeder 6 draws a part ofthe uppermost veneer A-1 in the stack and the veneer is then forwardedin the direction of the arrow. Ultimately, the veneer reaches anotherconveyor 19, and at this location adhesive 9 and hardener 10 are coatedon the surface of the veneer by flowing or spraying techniques. In thecase of apparatus station 2-5 no adhesive applying structure is providedsince the uppermost veneer in the plywood sheet does not require anyadhesive. As indicated above, the individual plywood veneers from theapparatus stations 2-1, 2-3 and 2-5 are delivered to the main conveyor 1so that the grain direction of the veneers is transverse to thedirection of the main conveyor. Accordingly, in accordance with thepresent invention the ad hesive is applied to the veneers at theseapparatus stations along a direction which is the same as the directionof travel of the veneers to the main conveyor. This technique operatesto apply adhesive to the veneer in the same direction as the grainthereof.

Generally, a veneer which is dried has a wave-like curve or ridge alongits grain, and when adhesive is applied by flow coating techniques aneven distribution of adhesive is achieved when the adhesive is appliedin the same direction as the grain. In the event adhesive is applied ina direction transverse to the direction of the grain, the back sides ofthe raised curves and ridges are not coated with adhesive. Ultimately,this defect is reflected in a very poor bond between adjacent woodveneers in the finished plywood sheet. The present method avoidsirregularities in the adhesive coating by applying the adhesive in thesame direction as the veneer grain.

After the individual veneer at apparatus stations 2-1 and 2-3 is coatedwith adhesive it is delivered to the leading surface of the vacuumconveyor 12 operated by a vacuum feeder 11, as shown best in FIG. 4. Thevacuum conveyor 12 has numerous small heads 13 fabricated or coated withmaterial, such as Teflon, for example, which does not stick to theadhesive coated veneer. The conveyor 12 has vacuum holes 14 and whenthese heads engage the veneer they anchor the veneer to the conveyor 12as long as the vacuum feeder 11 is operating. Ultimately, the adhesivecoated veneer is transported to a position directly above the mainconveyor 1 and a limit switch 15 operates an air cylinder 8 and a valve6" associated with the vacuum feeder 6 to effect a termination of thesuc-- tion delivered to the head 6'. Also, when the veneer istransported to the left, as viewed in FIG. 4, it engages a limit switch16 associated with an air cylinder 17, the vacuum feeder 11 and a valve11' to thereby terminate the vacuum delivered to the suction heads 13.When this vacuum is cut off, the adhesive coated veneer is droppeddownwardly onto the carrier 3. Subsequently, the lifter 5 is slightlyraised to a predetermined height determined by a limit switch 18 whichdetects the height of the supply. When the lifter 5 is elevated and theheight of the pile of veneer reaches the predetermined amount, the valve6" of the vacuum feeder 6 is opened to commence another feeding andcoating operation of a veneer to the main conveyor 1.

As indicated above, apparatus stations 2-2 and 2-4 deliver wood veneersto the main conveyor line 1 in a direction so that the grain of theseveneers is parallel to the direction of travel of the main conveyor. InFIG. 5 a stack of veneers A-2 are located on a lifter 5. The graindirection of these veneers is transverse to the direction in which theyare delivered to the main conveyor 1. The uppermost veneer in the stackon lifter 5' is delivered to a conveyor 23 by a suction device includinga vacuum feeder 21 and a head 21.. When the uppermost veneer in thestack is drawn toward the vacuum feeder 21 a conveyor 22 is operated tourge the uppermost veneer to the left, as viewed in FIG. 5. Next,adhesive 24 and hardener 25 are flowed or otherwise coated onto theveneer by applying them in the same direction as the grain. As thecoated veneer moves further to the left, as viewed in FIG. 5, on aconveyor 30, the veneer ultimately hits a limit switch 31 which causesthe veneer to take a right angle turn. The turning is accomplishedbyactivation of the limit switch 31 which causes a lifter 33 having bars32 to lift the coated veneer upwardly toward a vacuum feeder 26. Avacuum conveyor 27 associated with the vacuum feeder 26 cooperates witha vacuum feeder 26' to convey the coated veneer to the main conveyorline 1. The limit switches 15' and 18, and the lifter 5' operate in thesame'manner as described above in conjunction with switches 15, 18 andlifter 5. Also, the vacuum conveyor 27 is constructed in the same manneras described above in conjunction with the conveyor 12.

When the plywood veneer A-2 is finally conveyed to a position directlyover the main conveyor 1, the veneer hits a limit switch 28 to cut offthe vacuum operation. This causes the veneer to drop onto the carrier 3.The pushers 4' connected to the lines 4 then push the veneer in aforward direction from left to right, as viewed in FIG. 1. The pushers 4operate to pick up the newly delivered veneer from the carrier 3 andpush it on top of the already complied veneers located underneath thecarrier 3.

In accordance with the instant invention the present methodautomatically complies a back veneer, a sub-core thereon, a corethereon,an upper sub-core thereon, and lastly, an upper surface veneer.

Referring to FIGS. 8 and 9, a plywood B composed of five veneers isplaced on a belt conveyor 36 at the downstream end of the compilingconveyor 4. The plywood B is then conveyed forward until it engages alimit switch 36'. When the limit switch is engaged a slide conveyor 37operates to advance the plywood B to a table lifter 40. At the same timeas the advance of the slide conveyor 37 a catcher 39 advances. Thecatcher supports the top end of the plywood B. Operation of the slideconveyor 37 is terminated by contact of a limit switch 37-1 and a bar37'. The slide conveyor then returns and during such movement operates alimit switch 37-2. Limit switch 37- 2 operates an air cylinder 38' forlifting a stopper 38. The operation of the air cylinder 38 is terminatedby actuation of the limit switch 37-3. The return action of the catcher39 occurs when the limit switch 37-2 is engaged. The plywood B is piledon the lifter table 40, the rear end thereof being arranged in orderlyfashion by the stopper 38.

What is claimed is:

1. A method of producing plywood comprising a plurality of veneersincluding the steps of delivering a plurality of wood veneers from anequal number of stations to a main conveyor line, coating adhesive onthe surface of all but one of the veneers as the veneers are deliveredto the main conveyor line, pushing the veneers in a predetermineddirection by pushers that run along the main conveyor line, andcompiling the veneers on top of one another as they are pushed with theuncoated veneer uppermost in the pile, and wherein each wood veneer isinitially positioned at the main conveyor line at a location directlyabove and spaced from the line so that the pushers engage the veneer tomove it in the predetermined direction and compile it on top of anyveneers already picked up by the pushers.

2. A method as in claim 1 including the step of transporting theadhesive coated veneers to the main conveyor line by a vacuum conveyorhaving numerous small heads coated with material which does not adhereto the adhesive coated veneer.

References Cited UNITED STATES PATENTS 2,353,789 7/ 1944 Schieman 117-723,297,174 1/ 1967 Letchworth 214-6 F UX 3,367,823 2/1968 Clausen et a1....'156-557 X 6 3,616,090 10/1971 Larson 156-563 X 2,890,675 6/1959Cheever, Jr. l56562 X 2,772,197 11/1956 Kozdemba 144-309 R X 3,084,0904/ 1963 Rambo et a1. 156-299 3,133,850 5/1964 Alenius 156-299 X3,620,887 11/1971 Nelson 156-563 3,639,191 2/1972 B'eider et a1 161-56 XFOREIGN PATENTS 497,334 11/1953 Canada 156-563 OTHER REFERENCES TheJournal of Teflon, vol. 1, No. 4, p. 7, Du Pont, Wilmington, Del., April1960, TP 1180.17-16.

ALFRED L. LEAVI'IT, Primary Examiner T. E. BOKAN, Assistant Examiner US.Cl. X.R.

20 144-315 R; 156-563; 198-35; 214-6 F, 6 M

